Heart valve prostheses are used as mechanical valve devices to replace damaged or diseased natural heart valves. Known heart valve prostheses have an annular member or base carrying a suturing member adapted to be attached to the heart tissue. One or more valving members associated with the base controls one-way flow of blood through a passage in the base. Retaining means are associated with the valving member to hold the valving member in operative assembled relation with the base. The valving members commonly used are spherical members or balls, pivoting discs, poppet discs and leaflet members. Each of the heart valve prostheses have advantages as well as deficiencies. The operating characteristics of the heart valve prostheses are due mainly to the shape, operating structure and materials of the valving members and base. The limitations of the currently used heart valve prostheses include low efficiency and high pressure gradient across the valve opening, relatively high structural profile, localized sites of wear and fatigue, chemical breakdown and absorption of water and body fluids by the valve materials, regions of blood stagnation, structures that cause turbulence, regurgitation and eddy currents in the blood flow, structures that can cause formation of clots, hemolysis, damage blood tissue, and malfunction of the moving valving member.
Several valve designs have been proposed to use a pair of operating valving members. Mon et al in U.S. Pat. No. 3,312,273 disclose a bicuspid heart valve having a pair of resilient flapper members that move relative to each other to control the flow of blood through the valve passage. A diametrical pin serves as a fulcrum upon which the flapper member moves. Wada in U.S. Pat. No. 3,445,863 discloses a one-way heart valve having a base carrying a pair of valve plates. Each valve plate has a notch for receiving a portion of the base to pivotally mount the valve plate on the base. The valve plate is larger than the opening through the valve base. The valving members move from a generally horizontal position to about 60.degree. relative to the horizontal.
Heffernan et al disclose a heart valve assembly having two flexible flaps that are attached to inside wall portions of the valve body. The flaps flex relative to the body to open and closed positions to control the flow of blood through the valve passage.
A similar split leaflet cardiac valve is shown by Meyer in U.S. Pat. No. 3,589,392. The leaflets have curved shapes and have a flexible hinge portion held on the base. The leaflets flex relative to the hinge position to open and closed positions.
A central flow prosthetic cardiac valve, disclosed by Milo in U.S. Pat. No. 3,938,197, has a plurality of valve flaps pivoted to an annular base. The face is made of five interconnected members.
Servelle shows in British Pat. No. 1,160,008 a heart valve prosthesis having two flaps that are pivotally mounted on a base. An arch extended over the base has an inwardly directed portion which functions as a stop when the flaps are in the open position. A similar heart valve is disclosed by Kalke in the book Prosthetic Heart Valves by Lyman A. Brewer, pages 285-302.